// just a simple rectangle
pdf_setlinewidth($pdf, 5); //make the border of the rectangle a bit wider
pdf_rotate($pdf, 5); //rotate the coordinate system (NOT THE RECTANGLE !!!!!)
pdf_rect($pdf, 100, 100, 50, 50); //draw the rectangle
pdf_stroke($pdf); //stroke the path with the current color(not yet :-)) and line width

//note: the rect is not drawn untill we use pdf_stroke - try it out!!!